Plotting Name of States on Map using Node js and D3 in real time

I have been trying to plot the names of the states on the map using Redis Pub/Sub system, Node js and D3.
Issue is that when I type in a state for first time on a Redis channel, it is plotted perfectly, but when I type in the second state, nothing happens. Since I am new to D3.js, am not able to figure out the problem.
Any help will be appreciated. Thanks.